The Collaborative International Dictionary of English v.0.48:

Betime \Be*time"\, Betimes \Be*times"\, adv. [Pref. be- (for by)
   + time; that is, by the proper time. The -s is an adverbial
   ending.]
   1. In good season or time; before it is late; seasonably;
      early.
      [1913 Webster]

            To measure life learn thou betimes.   --Milton.
      [1913 Webster]

            To rise betimes is often harder than to do all the
            day's work.                           --Barrow.
      [1913 Webster]

   2. In a short time; soon; speedily; forth with.
      [1913 Webster]

            He tires betimes that spurs too fast betimes.
                                                  --Shak.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

34 Moby Thesaurus words for "betimes":
   after a while, ahead, ahead of time, anon, at times, before,
   before long, beforehand, beforetime, by and by, directly, early,
   ere long, ever and again, ever and anon, foresightedly,
   here and there, in a moment, in a while, in advance,
   in anticipation, in due course, in due time, now and again,
   now and then, once and again, oversoon, precociously, prematurely,
   presently, seasonably, shortly, soon, timely